The General Manager was the senior management position at Pigment Manufacturers of Australia Limited, overseeing all departments and reporting to the PMA Ltd board.

PMA Ltd had three General Managers during its twenty-one years of operation, the first being Hugh A. Grayson, who had held the equivalent position (Works Manager) at the Pigments Plant at Laverton (Imperial Chemical Industries of Australia and New Zealand Limited) prior to the formation of PMA Ltd.

As shown in the chronology below, Grayson's successor was D. K. Grant. From late 1982, Alan R. Barlee worked as Deputy General Manager under Grant having re-joined PMA Ltd after a number of years working with Imperial Chemical Industries Australia Pty Ltd. Barlee became General Manager in 1984, remaining in the role until production ceased in 1990, and overseeing the closure of the plant, and PMA Ltd, in 1991.

The PMA Ltd collection includes many files linked to the General Manager by distribution lists, inscribed names, or similar. In addition, Series 4, "Alan Barlee's Files", contains a comprehensive and well-organised group of records from his time as General Manager in the 1980s, and also incorporates papers from his predecessors.